6 BLOCK_EXPR, BREAK_EXPR, CLOSURE_EXPR, COMMENT, LOOP_EXPR, MATCH_ARM, MATCH_GUARD,
7 PATH_EXPR, RETURN_EXPR,
12 use crate::{utils::suggest_name, AssistContext, AssistId, AssistKind, Assists};
14 // Assist: extract_variable
16 // Extracts subexpression into a variable.
26 // let $0var_name = (1 + 2);
30 pub(crate) fn extract_variable(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
31 if ctx.has_empty_selection() {
35 let node = match ctx.covering_element() {
36 NodeOrToken::Node(it) => it,
37 NodeOrToken::Token(it) if it.kind() == COMMENT => {
38 cov_mark::hit!(extract_var_in_comment_is_not_applicable);
41 NodeOrToken::Token(it) => it.parent()?,
43 let node = node.ancestors().take_while(|anc| anc.text_range() == node.text_range()).last()?;
46 .take_while(|it| ctx.selection_trimmed().contains_range(it.text_range()))
47 .find_map(valid_target_expr)?;
49 if let Some(ty_info) = ctx.sema.type_of_expr(&to_extract) {
50 if ty_info.adjusted().is_unit() {
55 let ref_kind: RefKind = if let Some(receiver_type) = get_receiver_type(&ctx, &to_extract) {
56 if receiver_type.is_mutable_reference() {
58 } else if receiver_type.is_reference() {
67 let anchor = Anchor::from(&to_extract)?;
68 let indent = anchor.syntax().prev_sibling_or_token()?.as_token()?.clone();
69 let target = to_extract.syntax().text_range();
71 AssistId("extract_variable", AssistKind::RefactorExtract),
72 "Extract into variable",
76 match to_extract.syntax().parent().and_then(ast::RecordExprField::cast) {
77 Some(field) => field.name_ref(),
81 let mut buf = String::new();
83 let var_name = match &field_shorthand {
84 Some(it) => it.to_string(),
85 None => suggest_name::for_variable(&to_extract, &ctx.sema),
87 let expr_range = match &field_shorthand {
88 Some(it) => it.syntax().text_range().cover(to_extract.syntax().text_range()),
89 None => to_extract.syntax().text_range(),
92 let reference_modifier = match ref_kind {
93 RefKind::MutRef => "&mut ",
99 Anchor::Before(_) | Anchor::Replace(_) => {
100 format_to!(buf, "let {} = {}", var_name, reference_modifier)
102 Anchor::WrapInBlock(_) => {
103 format_to!(buf, "{{ let {} = {}", var_name, reference_modifier)
106 format_to!(buf, "{}", to_extract.syntax());
108 if let Anchor::Replace(stmt) = anchor {
109 cov_mark::hit!(test_extract_var_expr_stmt);
110 if stmt.semicolon_token().is_none() {
113 match ctx.config.snippet_cap {
116 .replace(&format!("let {}", var_name), &format!("let $0{}", var_name));
117 edit.replace_snippet(cap, expr_range, snip)
119 None => edit.replace(expr_range, buf),
126 // We want to maintain the indent level,
127 // but we do not want to duplicate possible
128 // extra newlines in the indent block
129 let text = indent.text();
130 if text.starts_with('\n') {
132 buf.push_str(text.trim_start_matches('\n'));
137 edit.replace(expr_range, var_name.clone());
138 let offset = anchor.syntax().text_range().start();
139 match ctx.config.snippet_cap {
142 buf.replace(&format!("let {}", var_name), &format!("let $0{}", var_name));
143 edit.insert_snippet(cap, offset, snip)
145 None => edit.insert(offset, buf),
148 if let Anchor::WrapInBlock(_) = anchor {
149 edit.insert(anchor.syntax().text_range().end(), " }");
155 /// Check whether the node is a valid expression which can be extracted to a variable.
156 /// In general that's true for any expression, but in some cases that would produce invalid code.
157 fn valid_target_expr(node: SyntaxNode) -> Option<ast::Expr> {
159 PATH_EXPR | LOOP_EXPR => None,
160 BREAK_EXPR => ast::BreakExpr::cast(node).and_then(|e| e.expr()),
161 RETURN_EXPR => ast::ReturnExpr::cast(node).and_then(|e| e.expr()),
163 ast::BlockExpr::cast(node).filter(|it| it.is_standalone()).map(ast::Expr::from)
165 _ => ast::Expr::cast(node),
169 fn get_receiver_type(ctx: &AssistContext, expression: &ast::Expr) -> Option<hir::Type> {
170 let receiver = get_receiver(expression.to_owned())?;
171 Some(ctx.sema.type_of_expr(&receiver)?.original())
174 /// In the expression `a.b.c.x()`, find `a`
175 fn get_receiver(expression: ast::Expr) -> Option<ast::Expr> {
177 ast::Expr::FieldExpr(field) if field.expr().is_some() => {
178 let nested_expression = &field.expr()?;
179 get_receiver(nested_expression.to_owned())
181 ast::Expr::PathExpr(_) => Some(expression),
196 Replace(ast::ExprStmt),
197 WrapInBlock(SyntaxNode),
201 fn from(to_extract: &ast::Expr) -> Option<Anchor> {
205 .take_while(|it| !ast::Item::can_cast(it.kind()) || ast::MacroCall::can_cast(it.kind()))
207 if ast::MacroCall::can_cast(node.kind()) {
211 node.parent().and_then(ast::StmtList::cast).and_then(|it| it.tail_expr())
213 if expr.syntax() == &node {
214 cov_mark::hit!(test_extract_var_last_expr);
215 return Some(Anchor::Before(node));
219 if let Some(parent) = node.parent() {
220 if parent.kind() == CLOSURE_EXPR {
221 cov_mark::hit!(test_extract_var_in_closure_no_block);
222 return Some(Anchor::WrapInBlock(node));
224 if parent.kind() == MATCH_ARM {
225 if node.kind() == MATCH_GUARD {
226 cov_mark::hit!(test_extract_var_in_match_guard);
228 cov_mark::hit!(test_extract_var_in_match_arm_no_block);
229 return Some(Anchor::WrapInBlock(node));
234 if let Some(stmt) = ast::Stmt::cast(node.clone()) {
235 if let ast::Stmt::ExprStmt(stmt) = stmt {
236 if stmt.expr().as_ref() == Some(to_extract) {
237 return Some(Anchor::Replace(stmt));
240 return Some(Anchor::Before(node));
246 fn syntax(&self) -> &SyntaxNode {
248 Anchor::Before(it) | Anchor::WrapInBlock(it) => it,
249 Anchor::Replace(stmt) => stmt.syntax(),
256 use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
261 fn test_extract_var_simple() {
270 let $0var_name = 1 + 1;
277 fn extract_var_in_comment_is_not_applicable() {
278 cov_mark::check!(extract_var_in_comment_is_not_applicable);
279 check_assist_not_applicable(extract_variable, "fn main() { 1 + /* $0comment$0 */ 1; }");
283 fn test_extract_var_expr_stmt() {
284 cov_mark::check!(test_extract_var_expr_stmt);
293 let $0var_name = 1 + 1;
305 let $0var_name = { let x = 0; x };
312 fn test_extract_var_part_of_expr_stmt() {
328 fn test_extract_var_last_expr() {
329 cov_mark::check!(test_extract_var_last_expr);
339 let $0var_name = 1 + 1;
351 fn bar(i: i32) -> i32 {
357 let $0bar = bar(1 + 1);
361 fn bar(i: i32) -> i32 {
369 fn test_extract_var_in_match_arm_no_block() {
370 cov_mark::check!(test_extract_var_in_match_arm_no_block);
376 let tuple = match x {
377 true => ($02 + 2$0, true)
385 let tuple = match x {
386 true => { let $0var_name = 2 + 2; (var_name, true) }
395 fn test_extract_var_in_match_arm_with_block() {
401 let tuple = match x {
413 let tuple = match x {
416 let $0var_name = 2 + y;
427 fn test_extract_var_in_match_guard() {
428 cov_mark::check!(test_extract_var_in_match_guard);
434 () if $010 > 0$0 => 1
441 let $0var_name = 10 > 0;
452 fn test_extract_var_in_closure_no_block() {
453 cov_mark::check!(test_extract_var_in_closure_no_block);
458 let lambda = |x: u32| $0x * 2$0;
463 let lambda = |x: u32| { let $0var_name = x * 2; var_name };
470 fn test_extract_var_in_closure_with_block() {
475 let lambda = |x: u32| { $0x * 2$0 };
480 let lambda = |x: u32| { let $0var_name = x * 2; var_name };
487 fn test_extract_var_path_simple() {
492 let o = $0Some(true)$0;
497 let $0var_name = Some(true);
505 fn test_extract_var_path_method() {
510 let v = $0bar.foo()$0;
515 let $0foo = bar.foo();
523 fn test_extract_var_return() {
533 let $0var_name = 2 + 2;
541 fn test_extract_var_does_not_add_extra_whitespace() {
555 let $0var_name = 2 + 2;
572 let $0var_name = 2 + 2;
597 let $0var_name = 2 + 2;
605 fn test_extract_var_break() {
618 let $0var_name = 2 + 2;
627 fn test_extract_var_for_cast() {
632 let v = $00f32 as u32$0;
637 let $0var_name = 0f32 as u32;
645 fn extract_var_field_shorthand() {
671 fn extract_var_name_from_type() {
685 let $0test = { Test(10) };
693 fn extract_var_name_from_parameter() {
697 fn bar(test: u32, size: u32)
704 fn bar(test: u32, size: u32)
715 fn extract_var_parameter_name_has_precedence_over_type() {
719 struct TextSize(u32);
720 fn bar(test: u32, size: TextSize)
723 bar(1, $0{ TextSize(1+1) }$0);
727 struct TextSize(u32);
728 fn bar(test: u32, size: TextSize)
731 let $0size = { TextSize(1+1) };
739 fn extract_var_name_from_function() {
743 fn is_required(test: u32, size: u32) -> bool
746 $0is_required(1, 2)$0
750 fn is_required(test: u32, size: u32) -> bool
753 let $0is_required = is_required(1, 2);
761 fn extract_var_name_from_method() {
767 fn bar(&self, n: u32) -> u32 { n }
777 fn bar(&self, n: u32) -> u32 { n }
781 let $0bar = S.bar(1);
789 fn extract_var_name_from_method_param() {
795 fn bar(&self, n: u32, size: u32) { n }
805 fn bar(&self, n: u32, size: u32) { n }
817 fn extract_var_name_from_ufcs_method_param() {
823 fn bar(&self, n: u32, size: u32) { n }
827 S::bar(&S, $01 + 1$0, 2)
833 fn bar(&self, n: u32, size: u32) { n }
845 fn extract_var_parameter_name_has_precedence_over_function() {
849 fn bar(test: u32, size: u32)
852 bar(1, $0symbol_size(1, 2)$0);
856 fn bar(test: u32, size: u32)
859 let $0size = symbol_size(1, 2);
867 fn extract_macro_call() {
893 fn test_extract_var_for_return_not_applicable() {
894 check_assist_not_applicable(extract_variable, "fn foo() { $0return$0; } ");
898 fn test_extract_var_for_break_not_applicable() {
899 check_assist_not_applicable(extract_variable, "fn main() { loop { $0break$0; }; }");
903 fn test_extract_var_unit_expr_not_applicable() {
904 check_assist_not_applicable(
918 // FIXME: This is not quite correct, but good enough(tm) for the sorting heuristic
920 fn extract_var_target() {
921 check_assist_target(extract_variable, "fn foo() -> u32 { $0return 2 + 2$0; }", "2 + 2");
928 let tuple = match x {
929 true => ($02 + 2$0, true)
939 fn extract_var_no_block_body() {
940 check_assist_not_applicable(
943 const X: usize = $0100$0;
949 fn test_extract_var_mutable_reference_parameter() {
966 let $0var_name = &mut s.vec;
973 fn test_extract_var_mutable_reference_parameter_deep_nesting() {
988 $0f.field.field.vec$0.push(0);
1002 let $0var_name = &mut f.field.field.vec;
1009 fn test_extract_var_reference_parameter() {
1016 fn do_thing(&self) {
1026 $0s.sub$0.do_thing();
1032 fn do_thing(&self) {
1049 fn test_extract_var_reference_parameter_deep_nesting() {
1055 fn do_thing(&self) {
1073 $0s.sub.field.field$0.do_thing();
1078 fn do_thing(&self) {
1096 let $0z = &s.sub.field.field;
1103 fn test_extract_var_regular_parameter() {
1110 fn do_thing(&self) {
1120 $0s.sub$0.do_thing();
1126 fn do_thing(&self) {
1143 fn test_extract_var_mutable_reference_local() {
1165 fn do_thing(&self) {
1172 let local = &mut S::new();
1173 $0local.sub$0.do_thing();
1194 fn do_thing(&self) {
1201 let local = &mut S::new();
1202 let $0x = &mut local.sub;
1209 fn test_extract_var_reference_local() {
1231 fn do_thing(&self) {
1238 let local = &S::new();
1239 $0local.sub$0.do_thing();
1260 fn do_thing(&self) {
1267 let local = &S::new();
1268 let $0x = &local.sub;